1. Field of the Invention
This invention relates generally to perpendicular magnetic recording write heads for use in magnetic recording disk drives, and more particularly to a write head with separated trailing, side and leading shields.
2. Description of the Related Art
Perpendicular magnetic recording, wherein the recorded bits are stored in a perpendicular or out-of-plane orientation in the recording layer, is a promising path toward ultra-high recording densities in magnetic recording hard disk drives. The recording or write head in perpendicular magnetic recording disk drives includes a write pole for directing a magnetic field to data tracks in the recording layer, and one or more return poles for return of magnetic flux from the recording layer.
The write head may also include a trailing shield (TS) of magnetically permeable material that faces the recording layer and is spaced from the write pole in the along-the-track direction by a nonmagnetic gap. The TS slightly alters the angle of the write field and makes writing more efficient.
The write head also typically includes a pair of side shields located on opposite sides of the write pole in the cross-track direction and separated from the write pole by a nonmagnetic gap layer. The side shields control the write width and eliminate adjacent-track-erasure. Typically the TS and side shields are connected or formed as a single-piece structure to form a wraparound shield (WAS) that generally surrounds the write pole. The WAS results in the TS and the side shields being formed of the same material and material composition and having the same throat height. A perpendicular magnetic recording write head with a WAS is described in U.S. Pat. No. 7,002,775 B2, assigned to the same assignee as this application.
What is needed is a perpendicular magnetic recording write head that has a trailing shield and side shields that are magnetically separated so that they can be formed of different materials or material compositions and can have different throat heights, to thereby independently control their magnetic properties to optimize performance of the write head.